We have looked at the synthesis of histones and non-histone nuclear proteins during DNA repair synthesis in human cells damaged with ultraviolet radiation and a powerful chemical mutagen and carcinogen. It is of interest that although damage to these cells with ultraviolet radiation and the carcinogen produces up to a fifty-fold increase in DNA synthesis (DNA repair synthesis), no new accumulation of histones or non-histone nuclear proteins was noted in these cells. Thus, although large chunks of DNA (in the range of 100-140 nucleotides) are removed during excision and subsequent repair, there is no evidence that new histones or non-histone nuclear protein synthesis need accompany this process. It appears that either nuclear proteins remain in place during repair synthesis or that they are removed and then subsequently re-utilized.